Balloon Animals / Book With Pump and Balloons, by Aaron Hsu-Flanders
This was actually the first book I ever read about making balloon animals. It has much to recommend it; it comes with some balloons (though you’ll need more; balloon twisting is a pop art, after all), and a simple palm pump (fits in the palm of your hand, and takes numerous squeezes to inflate a single 260 balloon), and is illustrated throughout with clear photographs and clear instructions. One of the nicest part of the book are the suggestions for changes to either make more types of balloon animals, or to customize your creations.
However, I can’t recommend it highly, simply due to its’ size. There simply aren’t very many animals covered in this small (128 pages, but 1.87″ x 9.83″ x 7.97″ in size) book. Part of that is due to the book’s greatest strength: the generous number of photographs, showing the step-by-step instructions of twisting dogs, cats, bears, elephants, etc.
In short, it’s a wonderful introduction to the world of balloon art; I recommend it for people who are just beginning, or wanting to get their feet wet and find out if this is for them. But for people who intend to go beyond the basics, I’d suggest looking at Captain Visual’s Big Book of Balloon Animals — which is well-named, and gives a better “bang for the buck.”
I rate it 3 clowns 
on a 5-clown scale.